Development of new effective chiral auxiliaries, catalysts and ligands continues to be an important endeavour in the field of organic chemistry because novel classes of chiral auxiliaries, catalysts and ligands not only offer additional synthetic opportunities but also provide new insights into fundamental chemical processes and new applications. Enantiomerically pure 1,1′-binaphthyl-2,2′-diol (BINOL) has been extensively utilized as a chiral auxiliary and ligand for both stoichiometric and catalytic asymmetric synthesis due to its axial dissymmetry and molecular flexibility. Of all the widely employed chiral ligands, the axially chiral 1,1′-binaphthyl-2,2′-diol (BINOL) has emerged as one of the most powerful ligands in asymmetric catalysis. The biaryl motif of this compound is considered to be a privileged structure in asymmetric catalysis.
Furthermore, BINOL-based synthons have become attractive molecular modules for applications in many fields such as chiral supramolecular recognition, crystal engineering and electronic materials. In this context a modification of the BINOL backbone would be highly valuable.
Efforts to modify the BINOL backbone lead to derivatives with different substituents at the C-3, C-4, C-6 and C-7 positions (Chen, Y, et al., Chem. Rev. (2003) 103, 3155). Notably, the rotational barrier of peri C—H bonds contributed significantly to the configurational stability of BINOL, hence direct modification of this special moiety provides another important strategy to change its scaffold. In addition, the chiral core defined by the two naphthyl rings provides an ideal chiral environment for the transfer of stereoinformation. The functionalization of the 8,8′-positions was also believed to have interesting implications in asymmetric induction. For example, F8-BINOL, H8-BINOL and H4-BINOL have been used to facilitate some asymmetric reactions with better enantioselectivities than BINOL itself.
It would thus be desirable to have further compounds with a backbone that is similar to that of BINOL, in particular for asymmetric synthesis. It is therefore an object of the present invention to provide a further derivative or analogue with a backbone that is similar to BINOL. This object is solved by the compound of claim 1.